Can you combine external drives into a MEGA external drive?

I have an external hard drive that I connect to my router and I back up important files to. But I'm reaching the external hard drive's limit of 1 TB. I was wondering if I could combine several external hard drives so they act like one HUGE MEGA DRIVE. :)

I was doing some research on the internet. Looks like you can combine external hard drives in RAID via a NAS but I don't have the money to waste on a NAS. I'm not sure what a spanned volume is but it looks like you'll need a spare operating system to make the drives work together which I don't have.

Can one of you experts just tell me the best way to get this done? It seems something simple.

Is there just a simple way to stack a lot of external hard drives together in an old spare computer case and have them simply act as a one huge external hard drive? So, the cost would only be the external hard drives themselves. For example, get like two 1-Tb hard drive and connect them together with RAID so it's ultra safe?

As this Microsoft Support note clearly states you can use external drives for Storage Spaces:

See https://support.microsoft.com/en-us/...storage-spaces for more info.
HTH,
--Ed--